标题: | 针对即时传输特性之MAC层资源分配方法 Priority-Based EDF Scheduling Algorithm for Real-time Service |
作者: | 吕宗奇 Lu, TsungChi 黄经尧 Huang, ChingYao 电子研究所 |
关键字: | 即时通讯;媒体存取控制层;最接近期限者先传之传送方法;real-time service;MAC;EDF |
公开日期: | 2007 |
摘要: | 由IEEE 802.15.3工作小组所制定的超宽频标准(Ultra Wide Band)是现今热门的标准之一,主要目标为在短距离内支援高速高品质的影音传输。为了要对高品质影音传输提供更好的QoS (quality of service)支援,并且为高速网路内不同类别的传输提供精准的传输顺位设定,我们提出了一个以传统EDF排程方法为基础所修改的新排程演算法。本演算法根据各个传输连结到达MAC层的封包大小以及所要求的传输速率来调整此封包的传输期限(deadline),对于同一个传输来说,此方法针对了各个传输的特性来提供精确的资源分配;对于不同传输来说,此方法也提供了不同的顺位控制。另外,我们也提出了传输辨识器(traffic identifier)的架构来辨别个别传输的真正QoS需求。最后,为了要实现新演算法,我们修改了802.15.3标准中的架构。模拟结果显示我们的新演算法和传统的方法比较后,不但在我们所设定的高顺位类型的传输模拟中有比较好的结果,对于低顺位类型的传输,也有相同甚至更好的结果。最难得的是,我们所提出的方法相当简单而且实用。 The Ultra Wide Band (UWB) standard developed by IEEE 802.15.3 task group is one of the popular candidates to achieve the goal of short range connection and high quality video/audio wireless transmission. In order to provide better QoS support for high quality multimedia applications and precise priority setting for various traffic types in high-data-rate wireless networks, a priority-based EDF scheduling algorithm is proposed. By adjusting each traffic’s deadline according to the frame size and required transmission rate, our proposed algorithm may provide precise resources for the same application according to traffic characteristics and different priority controls of different applications. At the same time, the traffic identifier is proposed. The main goal of the traffic identifier is to identify true QoS requirements. Finally we modified the MAC header and the superframe structure of standard MAC protocol in order to implement the proposed algorithm. Simulation results show that the proposed algorithm can not only guarantee a low error rate for high priority traffic, but also work better than other algorithms on low priority traffic. Most importantly, the proposed algorithm and modified MAC protocol are simple and realistic. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT009311628 http://hdl.handle.net/11536/78098 |
显示于类别: | Thesis |
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